Inspection Device for Inspecting a Building or Structure

2. A method according to claim 1, wherein for each point in time at which a set of 3D data is captured, the set of 3D data collected at that point in time is compared with a preceding set of 3D data using a scan matching algorithm, so as to determine a relative shift in position of the drone between capturing the two sets of 3D data.

3. A method according to claim 2, wherein the position of the drone is determined using a Simultaneous Localization and Mapping (SLAM) algorithm and optionally wherein the SLAM algorithm comprises a Graph-based SLAM algorithm.

5. A method according to claim 3, wherein executing the SLAM algorithm comprises updating a SLAM graph by performing a loop closure using one of the sets of 3D data, wherein performing the loop closure is carried out subject to the uncertainty in positions of points in the point cloud of said one of the sets of 3D data being above a threshold.

6. A method according to claim 2, wherein the scan matching algorithm comprises an Normal Distribution Transform (NDT) algorithm.

8. A method according to claim 7, wherein the volume of each cell is determined based at least in part on a distance between the one or more depth sensors and one or more of the points in the point cloud that are located in that cell; and optionally wherein the volume of each cell is chosen to be spherical.

10. A method according to claim 9, wherein in adjusting the volume of the cell, the cell is extended preferentially in a particular direction; and optionally wherein the cells are extended preferentially in the vertical direction.

13. A method according to claim 12, wherein for each time point at which a set of 3D data is captured, a scan matching algorithm is used to determine a horizontal translation in the x, y plane together with an estimate of yaw, and the odometry data are used in determining the roll/pitch and translation along the z axis.

14. A method according to claim 1, wherein the inspection data provides information concerning the structural integrity of the building or structure and/or wherein the inspection data is streamed in real time to a user device on which the user can visualize the inspection data.

15. A method according to claim 1, wherein each set of inspection data and each set of 3D data are timestamped.

16. A method according to claim 1, comprising overlaying a model of the building or structure onto the 3D map for visualization by the user.

18. A non-transitory computer readable medium comprising computer executable instructions that when executed by the computer will cause the computer to carry out a method according to claim 1.

19. A computer system comprising one or more processors configured to carry out a method according to claim 1.

22. A method according to claim 1, wherein the inspection is carried out in the absence of GPS signals being able to reach the drone.

23. A method according to claim 1, comprising: providing one or more sets of the inspection data for display alongside the 3D view of the environment, wherein for each of the one or more sets of inspection data, the 3D view of the environment displayed alongside shows the location of the drone in the 3D environment at the time the respective set of inspection data was captured.

24. A method according to claim 22, wherein the inspection is carried out within a structure that prevents GPS signals from reaching the drone.